HE COLOR TEST OF Zak et al. (1, 2, 3), in which a mixture of concentrated sulfuric acid, ferric chloride, and acetic acid is added to a solution of a steroid in glacial acetic acid, gives a purple color for steriods with the 5-ene,3$-ol grouping, and has proved useful for the clinical determination of cholesterol. These authors have qualitatively described the colors given by 22 other steroids ...

Introduction: Geologic evidence indicates that the K/T mass extinction occurred on 65 million years ago is caused by an asteroid or comet impact [e. g., 1]. However, the actual mechanism that caused the mass extinction is still very controversial. The impact generated sulfuric oxides are thought to cause an environmental perturbation and it is one of the most plausible hypotheses of the K/T kil...

The color reaction characteristic of cortisone and related compounds (with the 17,21-dihydroxy-20-keto grouping), which Porter and Silber (1) reported in 1950, has been used by a number of investigators to measure the “cortisone-like” metabolites of urine. To facilitate expression, we propose to give to the methods of analysis utilizing this reaction the term of “determination of 17-trioxystero...

in this study, the morphological and chemical properties of carob pods and carob beans as well as the effect of different extraction, and purification methods on the physical and chemical properties of the purified gums have been investigated. in order to dehusk carob beans, boiling water as well as acidic methods were used. the endosperm powder was prepared and the effect of endosperm powder c...

By applying the Arkenol process using highly concentrated sulfuric acid, various biomass feedstocks, including cedar tree, rice straw, newspaper, and bagasse, were successfully processed and converted into glucose and xylose for fermentation usage in a flash fermentation reactor in which the performance of National Renewable Energy Laboratory's patented rec-Zymomonas mobilis 31821 (pZB5) after ...

Recent ab initio calculations showed that amines can enhance atmospheric sulfuric acid-water nucleation more effectively than ammonia, and this prediction has been substantiated in laboratory measurements. Laboratory studies have also shown that amines can effectively displace ammonia in several types of ammonium clusters. However, the roles of amines in cluster formation and growth at a micros...

Dicarboxylic organic acids have properties that differ from those of sulfuric acid during hydrolysis of lignocellulose. To investigate the effects of different acid catalysts on the hydrolysis and degradation of biomass compounds over a range of thermochemical pretreatments, maleic, oxalic and sulfuric acids were each used at the same combined severity factor (CSF) values during hydrolysis. Xyl...